Many high-power devices require a pre-conditioner stage, a DC-to-DC power converter which allows the high-power device to operate with a wide range of input voltages. A representative example of a high-power device is a High-Voltage Generator, HVG, widely used in medical applications such as X-ray or magnetic resonance imaging, MRI. HVGs deliver powers in the range of 80 kW.
The pre-conditioner is generally supplied with a raw unregulated voltage, often a rectified three-phase main voltage. The specifications for the pre-conditioner may require it to handle a wide range of input voltages, such as nominal value plus/minus 50%. The output voltage, however, must be well regulated; the specifications may set a maximum peak-to-peak ripple in the range of for instance 5%. And these specifications must be fulfilled whilst delivering high power, even beyond 100 kW.
Because of the high power, linear regulation is unfeasible. When implementing such a pre-conditioner with a switched-mode power supply, all power components are subdued to high stress.
EP 1815582 B1 describes a pre-conditioner circuit having input terminals for receiving an input voltage, said pre-conditioner being for modifying said input voltage for application to a load, the pre-conditioner circuit comprising at least two pre-conditioner modules, each having an input and an output for connection to a respective load module.